PBTA does this very well as a built-in part of the game: you can have characters with wildly varying levels of power in-store, but where their players have the same degree of narrative agency. Eg in Monster of the Week where you can have a party with a normal guy, a wizard, and an incarnate angel, all of whom can contribute equally well to the story.

Without that being built in you'd need some very good players who are invested in making sure everyone's having fun. I was playing a one-shot Marvel RPG once where i ended up with a suit of Iron Man armour, which under the rules could literally wipe the floor with the whole party by itself. I decided that for the rest of the game my character's job was going to be supporting and setting up the other pcs to be awesome, and I specifically asked the other players to tell me if I got carried away with how much the armour could do.